University of Hohenheim

About: University of Hohenheim is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Population & Soil water. The organization has 8585 authors who have published 16406 publications receiving 567377 citations.

Life cycle assessment of energy generation from biogas—Attributional vs. consequential approach

Abstract: Many studies that apply life cycle assessment methodology avoid a strict differentiation between attributional (aLCA) and consequential (cLCA) life cycle assessment. The main distinction that can be made is that an aLCA approach describes a state of average production systems of an economic system while in contrast the consequential approach describes changes (induced by political decisions) in production systems within the economic system. The task of this study was to analyze a biogas system from an environmental point of view and thereby to work out the methodological differences of aLCA and cLCA approaches. The Life cycle inventory quantity primary energy demand (PED) as well as the impact categories global warming potential (GWP), eutrophication (EP), acidification (AP) and photochemical ozone creation potential (POCP) were analyzed. The aLCA approach was split into three scenarios, a physical, an economic and a core product focused one (with focus on the main product) to show the impact of by-product handling. The cLCA approach was split into a local scenario using on-site data and a general scenario using higher aggregated data to show the effects of substitution caused by the introduction of a new technology. The results of the two approaches were compared with the environmental impact of the current average and marginal German electricity mix. Global warming potential per functional unit varied between 3.8 g and 12.5 g of CO2 equivalent in the biogas scenarios. Compared to the average and marginal German electricity mix savings in PED, GWP and partly in AP and POCP can be achieved. However, high variations in the proportion to the reference electricity system, the total quantity results as well as the contribution of single processes to the total result were found. This makes it indispensable to distinguish accurately between the aLCA and the cLCA approach.

Effects of pulsed electric field treatment of apple mash on juice yield and quality attributes of apple juices

Abstract: The influence of apple mash treatment with pulsed electric fields (PEF) on yield and quality attributes of the resulting cloudy juices were investigated. Apple juice was produced at laboratory scale (400 g apples per lot) by mash treatment with pulsed electric fields at three different field intensities (1, 3, 5 kV/cm, n = 30 pulses) and manual pressing at room temperature. The juices were compared with untreated control juices of the same mash and with a juice after pectolytic mash treatment. Relative to the control samples, juice yield increased with increasing field intensities. The overall composition as described by pH, total soluble solids, total acidity, density, contents of sugar, malic acid and pectin, respectively, as well as the nutritive value with respect to polyphenol contents and antioxidant capacities (TEAC, FRAP, DPPH) of the PEF-treated apple juices did not significantly differ from the controls. Industrial relevance This paper addresses the composition of apple juice after mash treatment applying pulsed electric fields and maceration enzymes, respectively. Since substantial equivalence of products derived from novel technologies, such as PEF, relative to their conventionally produced counterparts is required according to European food law, this aspect is of great relevance, especially for commercialisation of fruit juices based on PEF technology. Furthermore, the nutritional value of juices produced at different pulsed electric field activities is of relevance for their marketing.

Effects of a vesicular-arbuscular mycorrhizal fungus and other soil microorganisms on growth, mineral nutrient acquisition and root exudation of soil-grown maize plants

Abstract: Maize (Zea mays L. cv. Alize) plants were grown in a calcareous soil in pots divided by 30-μm nylon nets into three compartments, the central one for root growth and the outer ones for hyphal growth. Sterle soil was inoculated with either (1) rhizosphere microorganisms other than vesicular-arbuscular mycorrhizal (VAM) fungi, (2) rhizosphere microorganisms together with a VAM fungus [Glomus mosseae (Nicol. and Gerd.) Gerdemann and Trappel], or (3) with a gamma-irradiated inoculum as control. Plants were grown under controlled-climate conditions and harvested after 3 or 6 weeks. VAM plants had higher shoot∶root ratios than non-VAM plants. After 6 weeks, the concentrations of P, Zn and Cu in roots and shoots had significantly increased with VAM colonization, whereas Mn concentrations had significantly decreased. Root exudates were collected on agar sheets placed on the interface between root and hyphal compartments. Six-week-old VAM and non-VAM plants had similar root exudate compositions of 72–73% reducing sugars, 17–18% phenolics, 7% organic acids and 3% amino acids. In another experiment in which root exudates were collected on agar sheets with or without antibiotics, the amounts of amino acids and carbohydrates recovered were similar in VAM and non-VAM plants. However, threeto sixfold higher amounts of carbohydrates, amino acids and phenolics were recovered when antibiotics were added to the agar sheets. Thus, the high microbial activity in the rhizosphere and on the rhizoplane limits the exudates recovered from roots.

Identification of Bacillus anthracis by using matrix-assisted laser desorption ionization-time of flight mass spectrometry and artificial neural networks.

Abstract: This report demonstrates the applicability of a combination of matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) and chemometrics for rapid and reliable identification of vegetative cells of the causative agent of anthrax, Bacillus anthracis. Bacillus cultures were prepared under standardized conditions and inactivated according to a recently developed MS-compatible inactivation protocol for highly pathogenic microorganisms. MALDI-TOF MS was then employed to collect spectra from the microbial samples and to build up a database of bacterial reference spectra. This database comprised mass peak profiles of 374 strains from Bacillus and related genera, among them 102 strains of B. anthracis and 121 strains of B. cereus. The information contained in the database was investigated by means of visual inspection of gel view representations, univariate t tests for biomarker identification, unsupervised hierarchical clustering, and artificial neural networks (ANNs). Analysis of gel views and independent t tests suggested B. anthracis- and B. cereus group-specific signals. For example, mass spectra of B. anthracis exhibited discriminating biomarkers at 4,606, 5,413, and 6,679 Da. A systematic search in proteomic databases allowed tentative assignment of some of the biomarkers to ribosomal protein or small acid-soluble proteins. Multivariate pattern analysis by unsupervised hierarchical cluster analysis further revealed a subproteome-based taxonomy of the genus Bacillus. Superior classification accuracy was achieved when supervised ANNs were employed. For the identification of B. anthracis, independent validation of optimized ANN models yielded a diagnostic sensitivity of 100% and a specificity of 100%.

Relationship between cell number, cell size and fruit size of seeded fruits of tomato (Lycopersicon esculentum Mill.), and those induced parthenocarpically by the application of plant growth regulators

Abstract: Application of GA3, IAA or 4-CPA to tomato ovaries induced the development of parthenocarpic fruit, which showed different growth rates. In the pericarp cell division and cell enlargement was affected differentially. GA3-induced fruits had considerably less but larger cells than seeded control fruits, IAA treatment resulted in the same number of cells but these were smaller and 4-CPA treatment induced fruits with about 20% more cells. Reduction in cell number had a similar effect on final fruit size as diminution of cell size. A reduction in the number of cell division centres (area around vascular bundles) as well as changes in the degree of endoploidy are possible reasons for the observed reductions in cell numbers. Hormonal causes for the different number and size of pericarp cells after the various treatments are discussed.